A new method for experimentally investigating spontaneous speech and speech perception has been developed. The paradigm seems effective in exploring the psychological units of production and perception: initial results indicate that the surface structure clause is the talker's primary unit and the beginning of such a clause requires more concentration than the end. For the listener, the deep structure clause is indicated as the primary unit. Future analyses, based on data already collected, focus on 3 issues: what are the units of planning and decoding in production and comprehension; what is the role of the grammar in speech processes; what significance do certain behavioral characteristics of speech have.